Automatic weft straightener control and method



2 Sheets-Sheet l R. H. TUTTLE ET AL AUTOMATIC WEFT STRAIGHTENER CONTROL AND METHOD May 19, 1953 Filed Sept. 15, 1950 Elam/a0 H 7137 H5, JoH/v 7T MAdCISAA JJR.

an FRED W. .Srueravmvf,

- INVENTORS.

AfroRNEYs.

EEEEq y 19, 1953 R. H. TUTTLE ET AL 2,638,656

AUTOMATIC WEFT STRAIGHTENER CONTROL AND METHOD Filed Sept. 15, 1950 2 Sheets-Sheet 2 Ric/MR0 H Tum E, Jomv 7.' Mnglsnnc, JR.

F1? W STURTE vA/v INVENTORS.

ATTORNEYS.

Patented May 19, 1953 AUTOMATIC WEFT STRAIGHTENER CONTROL AND METHOD Richard H. Tuttle, Leaksville, John T. MacIsaac, Jr., Spray, and Fred W. Sturtevant, Leaksville, N. C., assignors to Marshall Field and Company, Chicago, 111., a. corporation of Illinois Application September 15, 1950, Serial No. 184,982 9 Claims. (Cl. 2651) This invention relates to improvements in weft straighteners of a type employed. in the finishing of web materials such as fabric and the like and relates more especially to an apparatus for'insuring'parallelization of weft yarns as they are moved past a given point such as, for example, in the passage of the woven fabric from a mangle to a tenter. Heretofore, various attempts have been made to provide apparatus for straightening the weft of Woven fabrics in order to insure that the weft yarns may be disposed in right-angular relation to the warp yarns and to further insure that the 'weft yarns shall be straight from one selvage to the other of the fabric. Althoughthe mechanical 'means heretofore used for this purpose may have operated satisfactorily in order to straighten the weft yarns, the means for controlling the mechanical means heretofore in use has necessitated the passage of light rays through the fabric and, upon a series of weft yarns being bowed or skewed, certain of the light rays would more effectively penetrate the fabric than would other of the light rays thus resulting in the mechanical means being operated to overcome the skew or bow in the fabric.

It is evident that the more closely woven a fabric may be, or in the event of the material passing the lighting means not becoming of an uneven density throughout its width upon the weft elements thereof being skewed or bowed, the light rays could not penetrate the material passing thereby and, thus, the mechanical means for straightening the weft elements may not be effective. It is therefore an object of this invention to overcome such defects by providing weftwise extending lines or marks in spaced relation to each other throughout the length of the material being processed, these lines or marks being made of a luminescent material which, when applied to the web material being processed, would be invisible to the naked eye but would absorb light of constant intensity when continuously exposed to a uniform source of radiant energy, of the proper wave length, and this light is remitted to certain types of photoelectric scanners and, in so doing, would transmit impulses to a suitablemechanical means for correctingany lag in the web material being processed in the event the coinciding lumi- 'nescent element applied to the web material is not positioned in alinement with the photoelectric scanners for effecting the completion of a circuit to the mechanical weft straightening means.

' The terms ultraviolet and infrared as used hereinafter are used as examples only and are not to be construed as a limitation inasmuch as the science of electronics includes a great many types of lamps which may emit rays of varying wave length which are not visible to the naked eye'and for which there are certain luminescent elements which may become visible to the naked eye only when subjected to a source of radiant energy of the proper wave length. In some instances, it may be that one particular luminescent element may be excited by the rays of several types of lamps and not be excited by another type of lamp while, in other instances, a particular type of luminescent element applied to the web material may be responsive to the rays of only one particular type of lamp. Hereinafter, particular reference will be made to ultraviolet lamps andrays which are to be accepted as exemplary of the category in which the many types of invisible or Black light rays may be placed.

Also, the term luminescent is used to denote any material which, when applied to any surface, will be invisible to the naked eye under natural or normal lighting conditions but will emit useful, visible light after having absorbed radiant energy of a shorter wave length, outside of the visible spectrum.

Some of the objects of the invention having been stated, other objects will appear as the description proceeds When taken in connection with the accompanying drawings in which- Figure 1 is a diagrammatic view showing a typical mechanical means for removing skew or bow from a moving sheet of web material such as a woven fabric and showing one arrangement of the improved apparatus for controlling the mechanical Weft straightening devices;

Figures 2, 3 and 4 are diagrammatic views" of different conditions of skew or bow of the web material which are provided to facilitate a clear understanding of the invention.

Inasmuch as it is believed that the improved control means for the mechanical weft straightening apparatus would predominately be used in the finishing of textile materials, the web material shall herein be more generally referred to as a woven material or fabric. Referring more specifically to the drawings, a length of web material l(l, which may be a length of woven material or fabric, is shown which is passed between 2. pair of rolls'll and 12, such as mangle rolls, and extends, preferably in a horizontal plane, to pass under an idler roll l3 then upwardly over a canting roll [land again downwardly beneath a second idler roll 55 spaced from the idler roll [3 after which the woven material It passes between a pair of longitudinally spaced or bowed rolls l6 and H and thence into a succeeding processing machine, such as a .tenter, having endless chains :29 and 2|. These chains 20 and 2| pass around respec-- tive end pulleys 22 and 22a which are driven at equal speeds in any desired manner. The rolls I3, 14 and 15 are parts of aweft straightener broadly designated at 23 and the rolls 1 and 4"! are parts of a bow straightener broadly designated at 24. The weft straightener and the bow straightener are substantially the same as those shown in United States Patent No. 2,492,737 of December 27, 1949.

Although the weft and bow straighteners shown in Figure l are substantially the same as those shown in said patent, it is to be understood that the present control means need not be limi ed to controlling weft and bow straighteners of the type shown, there being many other types of weft and bow straighteners with which the present invention may be associated, one of these being of a type such as manufactured by .Mount Hope .Machine Co, Fifth Street, Taurrton, Mass.

The canting roll I4 is journaled for rotation in suitable bearing blocks 25 and :25. These hear-- ing blocks are connected to a screw shaft 32, 1'

through links .2?! and .28, each having a nut 31 "thereon, only one of which is shown, the nuts being threaded on the screw shaft .32 which may be rotated in either direction by means .of a

reversible skew correction electric motor 34 to which it is connected by means of gears 35 and .36.. As the web or woven material i6 passing from the mangle 330115 N and .12 is skewed, the skew can be corrected by rotation of the gear 36 driven by the motor 34 in the proper direction to elevate one end of the cantin-g roll M and to lower the opposite end thereof.

Now, in the event of the weft {of the material :being :bowed, the weft o-r skew straightener :23 would not .be eifective in correcting the bowed condition of the web material passing therethrough and therefore the bow straightener .24 is provided. The bowed rolls [6 and H are promid-ed with stub shafts which are rotatably mounted in bearing blocks 49 and M which are disposed adjacent opposed sides of the path of the fabric or woven material ill. A bow correction electric motor 52 is mechanically coupled to the shafts through beveled gearing -44 so as :to

rotate :the bowed rolls inopposite directions. On

:its way to the tenter the web material passes'over an idling roll 455 and beneath the bowed roll 1:6, over the bowed roll H and beneath an idling roll 4.6.

it is evident that upon the bowed rolls i6 and ,i J being moved various distances from each-other at their centers, they will effect a change in the contour of the fabric ,passing thereby and will thus straighten a bowed weft. A detailed description as to the manner in which the rolls l6 and all straighten a bowed weft is deemed unnecessar-y since this is clearly shown and described in said patent, the present invention being concerned with an improved control means for the skew straightener 23 and the bow straightener 2 4 to cause them to be positively rendered operable in the desired manner upon a skewed or bowed weft in the web material passing ag-iven point.

An important feature-of the present invention is the utilization of .a normally invisible light absorbing and reemitting element which may be applied to the web material ID at any desired spaced points along the length thereof, each of these applications of the light absorbing and reemitting element preferably being applied in .a straight line-extending from oneselvage to the other of the web material is and being normally disposed at right angles to the longitudinal axis of the web material 10. The lines of the light absorbing and reeniitting element are indicated at L in Figures 1 to 4 inclusive.

Now, heretofore the use of lines of a light absorbing and reemitting element, such as the lines L .in Figure 1 on a web material, such as fabric, has been prohibitive inasmuch as it would either have to :be removed in certain processing operations prior to its being finished or it would have to be of such color as to blend in with the material being processed. Since woven materials include a number of different designs in many instances and, in other instances, a woven material, such as sheeting, cannot have marking or disfiguraticns thereon of any kind, Suchv a marking has been deemed impractical and, thus, no attempt has been made to use a marking of this type. However, the lines LzShOWJQ in Figure 1 are, in this instance, formed of a light absorbing and reernitting element which is invisible under natural light rays but which is visible when subjected to light ,r-ays .of a proper wavelength such as the rays of infrared-or ultraviolet ,lamps. Thus, although the web material may still contain the light absorbing. and reem-itting element therein or thereon aft-er it has been completely processed, this light absorbing and reemitting element, which is not responsive to natural light rays, would be invisible and thus would not be detrimental to the appearance of ,a finished article :made from the web material 40.

The lines ,-L on the fabric or web material are preferably applied thereto in .a liquid form in which --the liquid or dispersing ingredient has fluorescent or phosphorescent pigments mixed therewith. The most commonly known fluorescent pigments includev zinc sulphides and zinc and cadmium sulphides combined with a suitable dispersing medium. There are many .types of ingredients which may produce an ultraviolet sensitive marking on fabric, one of these being a so-cal-led National Eantom-Fast Formula Number 9&6, manufactured by the National Marking Machine Company, 4026 Cherry St" Cincinnati 23, Ohio. In experiments made using this ink, .the ink was applied to a fabric before any finishing operations took place, and after which the fabric was passed through sheer-hog, singeing and bleaching operations and the mark still retained its original visibility under ultraviolet light.

An ultraviolet sensitive marking may also be made on fabric by the use of a'fluorescent stilbene derivative of a type manufactured by Geigy Company, 89 Barkley St... New York 8, N. Y., under their trade name Tinopal BVA.

Other ultraviolet sensitive marking materials from which the lines L on the web material It may be formed include a fluorescent pigment of a type manufactured by the New Jersey Zinc Sales Company, Front St, New York 7, N. and which is termed their Horse Head 2,0100 series of fluorescent pigments. These last-named pigmentsmay be obtained in a water soluble condition and applied from a water solution .of suitable strength or may be insoluble in water but soluble in other liquids such as mineral oils or so called volatile solvents or may be of the type which have a particular capacity for absorption and reemittance of light from a variety of sources,

but may be such materials as are invisible to the naked eye under normal light conditions but which would allow increased or decreased reemission of light under particular light source circumstances. In other words, in the latter instance, the lines L may be formed of a normally invisible material which would permit rays of incandescent or natural light to pass through the material.

Inasmuch as the lines L should normally extend at right angular relation to the longitudinal axis of a fabric, it is preferable that the light reflecting material be applied to the fabric at the time it is woven. In this instance, certain picks could be woven with a yarn to which a coating of the reflecting element may have previously been applied thus insuring that both the weft yarns and the warp yarns are straight at the time the light reflecting element is applied to the fabric. However, it is evident that the light absorbing and reemitting element may be manually applied vsuch as with a rubber stamp, a pen, a case marking brush, a small paint brush or in any other desired manner.

Now, referring to Figure 1 there will be observed a plurality of light responsive electrical elements, there being three of these elements shown and indicated at 55, 5| and 52. These light responsive electrical elements 50, 5| and 52 shall be hereinafter termed photoelectric cells, phototubes or scanners. There may be any desired number of these scanners arranged to extend in a line "transversely of the path of travel of the web material I5.

Now, since the material from which the line L is -made remains invisible under natural light and may remain invisible under certain other types of light rays, there is provided a plurality of lamps 53 which extend in a line at right angles to the path of travel of the material it] and the rays of light from the lamps 53 are adapted to impinge upon each of the lines L as it passes thereby to 'cause light to be absorbed and reemitted from said lines. It is evident that these lamps 53 must be of a type which will have a proper wave length for the particular type of normally invisible material from which each of the lines L is formed.

Since the description heretofore has referred specifically to fluorescent pigments and other materials which are visible under ultraviolet rays, the lamps 53 should be ultraviolet lamps, the rays of which will cause rays of light to be absorbed and reemitted from the areas of the fabric or web material on which the lines L appear. Thus, these rays cause light to be absorbed and reemitted from each of the lines L as they pass thereby to the photoelectric scanners 50, and

52, simultaneously, in the event of the lines L which are used as an exciter for the line L. The photoelectric scanners and the means for'amplifying the electric current controlled thereby in response to the rays of light from the line L,may

be of a type such as ismanufactured by West- .inghouse Electric .Corp.",-P iO..Box 2025, Bufialo 5,

N. Y. and which is termed a RR-ll register regulator and combination scanner for transmitted or reflected light.

In the present instance there are shown wires and '55, 51 and 58 and 59 and which are connected at one end thereof to the respective photoelectric scanners 50, 5| and 52. It will be noted that the lines of sight of the photoelectric scanners 55 and 5| are disposed inwardly of but closely adjacent the respective selvages of the web material It! and the scanner 52 is disposed so the line of sight thereof will impinge upon the web material In at a point in alinement with the points at which the lines of sight of the photoelectric scanners 55 and 5| impinge upon theweb material It and intermediate the selvages of the web material Ill. The two outside photoelectric scanners 55 and 5| are provided particularly to prevent skew of the material H3 and the centermost photoelectric scanner 52 is provided in cooperation with the scanners 55 and 5| to prevent bow in the web material H) as it moves thereby. Therefore, the wires 55 and 58 are connected to opposed sides of a bridge 52 of a power amplification unit broadly designated at 59'. Wires 55 and 51 are connected to opposed sides of the third and fourth arms of the bridge represented by resistors 63 and 64. A direct voltage of substantially constant value is supplied to the input terminals 650. and 50b of the bridge 62 from a source of regulated voltage which is represented by the two supply conductors 55 and 65. The output terminals 550 and 65d of the bridge 62 are connected to the input control terminals 61a and 51b of a suitable balanced electric valve amplifier 6T.

Direct voltage is supplied to the power input terminals 610 and Bl'd of the amplifier from a suitable source such as the supply conductors 65 and 66. The output terminals 516, 61-), 61,1 and 51h of the amplifier are connected to the control input terminals Illa, 15b, 15c and 15d of a balanced power amplifier 10. Alternating voltage is supplied to the input side of the power amplifier m by two supply conductors 1| and 12.

The power output terminals me and 10f are connected to the armature of the skew correction motor 34.

Now, this skew correction apparatus 25 tunetions in substantially the manner described in said Patent No. 2,492,737 and is not claimed as a part of the present invention, the features of the present invention residing in the manner in which light rays are reflected to the photoelectric scanners 55, 5| and 52. However, in order that the function of the apparatus may be clearly understood, the manner of operation of the skew correction apparatus 55 will now be given.

When the bridge 52 is balanced, that is, when the photoelectric scanners 55 and 5| receive substantially equal amounts of light from the line L on the web material it, the voltage across the output terminals 550 and 55d of the bridge is zero. Consequently, the voltage at the output terminals file and 511 of the amplifier 6'! is equal to the voltage of the terminals 61g and 5771.. This results in both paths of the power amplifier 10 being equally energized. Thus, the current in each path is rectified half way, and these currents are supplied to the armature of the motor 56 in opposite directions so that the net energization of the motor 54 is zero and the gear 35 is stopped. The magnitudes of the balanced output voltage of the amplifier 5'! are relatively low is illustrated in Figure 1.

scene so 7 and the opposin circulating current in the motor aimature are correspondingly lower.

Now, when the bridge 52 becomes unbalanced in one direction, that is, when the photoelectric scanner so receives more light than the photoelectric scanner 5 I, the current in one path of the power amplifier i is increased and the current in the second path is're'duced to zero. This results in the motor rotating in :a corresponding direction. It is evident that, if the bridge '82 becomes unbalanced in the reverse direction, the current in the second path is increased while the current inthe first path is reduced to zero and the motor will rotate in the reverse direction.

The appearance of the lines L on the web material i?) when the web material has no skew It is evident that the ultraviolet ray absorbing and reernitting material from which the line L is formed extends at right angles to the web material as and also extends in a straight line from one selvage to the other thereof and this would result in equal amounts of light being received by all three of the photoelectric scanners c, and 52 with the result that the bridge 5%; is balanced and the correction motor 34 is at a standstill.

Figure 2 shows the line L extending at an angle relative to the selvages of the web material as it would be in the event or the material it being skewed. Figure 3 shows the line L extending transversely of the web material ill but being bowed in the middle and Figure l shows the line L extending at an angle and also being bowed. The power amplification unit for the electric motor 42 is broadly designated at 'M and is identical to the power amplification unit 59' fo the skew correction motor 36). Since the electrical connections for the unit '14 are identical to those of the unit 59, only a brief description will be given of the unit l4, this unit it including a pair of wires 35 and '56 which extends from the motor 42 to a power amplifier H for controlling the motor 42. The power amplifier ll is controlled by an amplifier 86 which is, in turn, controlled by a bridge 8!. One arm of the bridge 3 is connected to the centermost photoelectric scanner 52 by means of the wires 59 and Bi) and the other arm of the bridge is connected to the outside photoelectric scanners 5i and 5!, there being wires 82 and 83 extending from the corresponding arm of the bridge 8! and being connected intermediate the ends of the respective wires 55 and 56. One end of wires 84 and 85 is connected intermediate the ends of the respective wires 82 and 83, the other ends of the Wires 84 and $5 being connected intermediate the ends of the respective wires 58 and 5?.

It is thus seen that the two outside photoelectric scanners Fill and 51 cooperate with the middle photoelectric scanner 52 to control the operation of the bow correction motor Q2. It is evident that, upon the llne L being straight and in alinement with the row of photoelectric scanners 5b, 5! and 52, both bridges 62 and 8! would be balanced.

Now, although the opposed ends of the corresponding line L may be disposed in parallel relation to the outside photoelectric scanners 5d and ill, if this line happens to be bowed in one direction or the other, as shown in Figures 3 and 4, it is evident that the outside photoelectric scanners 50 and 5| will receive light which has been absorbed by and reemitted from the lines L in ad- Vance of or after the middle photoelectric scanner 52. Depending upon whether the middle 8 scanner 52 receives the light from the lines L in advance or after it is received by the outside photoelectric scanners 50 and 51, the bridge 8=l of the unit i l is unbalanced at the corresponding side and the bow correction motor 42 is thus energized to rotate the bowed rolls ['6 and I! either towards or away from each other sufficiently to eliminate the bow in the web material it, whereupon all three photoelectric scanners 5e, 5! and 52 will receive equal amounts of light from the lines L and the bridges BI and 82 "of the respective units 74 and 59 be rebalanced. As a result, both of the respective correction motors t2 and 34 will be deenergized and stopped.

It is thus seen that we have provided an improved means for controlling the operation of the correction motors 34 and 42 wherein any type of material. being processed, to which a coating of a normally invisible light absorbing and reemitting element may be applied, either to the surface thereof or through impregnation thereof, may serve as its own medium for controlling any desired electrically operable mechanism to insure that the attitude of the material being processed may. after passing a given point, be constant.

There are many advantages to this method of actuation of electrical devices, the basic advantage being that the-mark or marks applied to the weft material will be entirely invisible to the naked under ordinary lighting conditions and thus will never have to be removed from the material and may be applied to the material in the primary stages of its manufacture. Although the web in aterial may be passed through many washing, bleaching or dyeing operations the marks or lines, such as the lines L in Figure 1, may remain visible under the rays of a proper wave length for the particular material from which the lines L are formed.

In the event of the lines L being formed at the time of weaving a fabric to be processed, it is evident that the lines will be absolutely parallel to the warp filling yarns in the material. Also, the markings may be applied to the material at any predetermined angle relative to the longitudinal axis of the web material so as to insure a certain distortion in the material if so desired. Also, these marks may be applied to the material so as to be used for guidin in any predetermined manner such as in cutting a fabric along a predetermined line etc. In other words, the markings made with a material which may be invisible to the naked eye under ordinary lighting conditions can be used for controlling the straightness of the weft and the selvage and will insure accurate enough response of the electrically operable mechanism controlled thereby so that the fabric may be cut parallel to the filling.

This same type of marking can be used with such control of cloth as for slitting operations, printing range, folding, rolling up operations, layout for cutting, etc. It is evident that it may also be used for the control of Woven pattern materials where the pattern is of such a nature as to render its use for registration purposes difficult or impossible. This particular means is not limited to white or solid color fabric but may be used with any combination of colors without affecting the color of the fabric. These markings may be used with transparent, translucent or opaque materials as well as fibrous, strand, grained, woven or other web materials.

In the drawings and specification, there has been set forth a preferred embodiment of the invention and although specific terms are employed,

they are used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention being defined in the claims, i

We claim:

l. In an apparatus for removing. skew and bow from a moving length of web material, said apparatus having electric reversible motors associated therewith for correcting undesirable skew and bow in the web material and also having a source of electrical energy, an improved means for controlling the electric motors compris'in a plurality of spaced markings of luminescent'material invisible to the naked eye under normal lighting conditions disposed'on the web material,

illuminating means past which the markings on the web material pass, said illuminating means having rays of a wave length coinciding with the material from which the markings are formed so as to render said markings visible by reemitting light therefrom, photoelectric means responsive to the rays of light absorbed by and reemitted from said markings on the web material by the illumi nating means and means controlled by said photoelectric means for controlling the operation of the electric motors,

2. A method of controlling an electrically operable mechanical means for controlling the contour of a moving length of web material wherein photoelectric means are associated with said electrically operable mechanical means which includes the application of spaced markings of a material which is invisible under normal lighting conditions but which is visible under light rays of a particular wave length to the web material, subjecting these markings to light rays of a wave length coinciding with that of the marking material whereby said light is absorbed and reemitted therefrom to the photoelectric means for effecting operation of the electrically operable means for controlling the contour of the web material.

3. In a weft straightener for a moving length of material, said weft straightener having photoelectric means for varying the position of the selvages of the web material with respect to each other and for varying the medial portion of the web material with respect to the selvages, an improved means for transmitting light rays to the photoelectric means comprising a plurality of spaced light absorbing and reemitting elements adhering to and extending transversely of the web material, said light absorbing and reemitting elements being invisible to the naked eye under normal lighting conditions, illuminating means disposed adjacent said photoelectric means, said illuminating means projecting light rays therefrom which are invisible to the naked eye under normal conditions, the rays projecting from the illuminating means being of a wave length coinciding with the light absorbing and reemitting elements so as to cause light to be absorbed and reemitted therefrom upon impinging thereon and the photoelectric means being so positioned as to receive the rays of light reemitted from each of the light absorbing and reemitting elements as they successively move into the plane of the rays from the illuminating means.

4. In a weft strainghtener for a moving length of fabric material having warp yarns and weft yarns, spaced luminescent means on the material and extending parallel to the weft yarns, a uniform source of radiant energy of predetermined wave length, said luminescent means being visible only upon being exposed to said uniform source of radiant energy of predetermined wave length, transversely spaced photoelectric means disposed adjacent the path of the fabric and directed at points along the width of the fabric in a straight line, said photoelectric means being responsive to the luminescent means as it is subjected to the radiant energy and means controlled by said photoelectric means for moving said weft yarns with respect to said warp yarns. V

5. That method of handling cloth to correct the angulation of the weft with relation to the selvages thereof which comprises forming in the cloth a plurality of weftwise extending relatively narrow spaced light absorbing and reemitting elements between which non-light absorbing and reemitting areas are formed and moving the cloth past a source of light and past elements responsive to said reemitted light for changing the angular position of the weft with relation to the selvages of the cloth.

6. That method of straightening bowed fillings in a moving web of cloth wherein photoelectrical- 1y operable bow straightening instrumentalities are employed which comprises weaving spaced portions of the filling threads from a yarn which has a. material thereon which is invisible to the naked eye but which is visible when subjected to light rays of .a predetermined wave length and subjecting the moving web to light rays of such wave length as to cause light to be absorbed and reemitted from the spaced portions to said photoelectrically operable bow straightening instrumentalities for bringing the weft threads to right angular position with relation to the selvages of the web.

'7. That method of handling cloth in a finishing operation, slitting operation, printing operation, folding operation, rolling up operation, cutting operation and the like which comprises providing the web with spaced substantially transverse areas impregnated with a luminescent material which is invisible to the naked eye but which is visible when illuminated by light rays of a predetermined wave length and successively scanning said spaced areas with a plurality of sources of light of a predetermined wave length simultaneously with light responsive elements and controlling the above described operation by the scanning operation.

8. That method of changing the angularity of the weft threads of a length of clothrelative to the warp threads while the cloth is moving which comprises subjecting the cloth to a plurality of transversely spaced sources of light with associated scanners so disposed as to impinge upon the cloth and providing the cloth with spaced areas having filling threads impregnated with a coloring matter which is invisible to the naked eye but which is visible when subjected to light rays of a predetermined Wave length and then exerting a retarding action on certain portions of the cloth in accordance with the scanning of the sources of light to bring the weft threads into the desired position with relation to the wrap threads at all points transversely of the cloth.

9. Apparatus for straightening bowed or skewed filling threads in a piece of web material and including work performing instrumentalities, comprising means for directing a webof material having spaced substantially transverse areas impregnated with a luminescent material invisible to the naked eye but which is visible when illuminated by light rays of a predetermined wave length, providing a source of light of a predetermined wave length to successively scan a plurality of said transversely spaced areas, means for moving the web past aid sources of light, photoelectric means adjacent the path of said web material for also scanning said areas simuht-anequsly with the source of light and means con-. trolled by the scanning operation for energizing eertajx; of the work performing instrumentalities for operation upon the web material in accordalgoe with the scanning operation.

RICHARD H. TUTTLE.

JOHN T. MACISAAC, JR.

FRED W. STURTEVANT.

Number Name Date Huntress Sept. 8, 1931 Redman June 24, 1941 Kallmann 1 Feb. 18, 1947 Vose et, a1 Sept. 23, 1947 Gantner, Jr, Sept. 28, 1948 Gottschalck May 1'0, 1949 Dunn Dec. 27, 1949 Hall Mar. 27, 1951 

